agree, double impatiens. But "needs water" doesn't seem to fit with "we have had very rainy and humid weather." It could be wilted like that because it drowned. That would be worse news, because easier to bring plants back from under watering than over.
You can try getting it in out of the rain, under cover. I would take it out of the pot and check the roots. If they are black and mushy, your plant is a goner. If white and firm, repot in fresh dry soil and water just enough to moisten. Never leave it sitting in water. And impatiens are shade plants, that will burn up in too much sun.